Abstract: A control system for a guided missile includes means for rotating the missile about its axis, a discharge nozzle so directed that its thrust exerts a lateral force on the missile and an associated reaction motor arranged to deliver, in response to a suitable signal, a thrust of suitable timing and duration to correct the missile trajectory. A suitable reaction motor has a combustion chamber in communication with the discharge nozzle by way of a relief valve, a compressible fuel tank pressurized by gases from the combustion chamber by way of a differential piston pump actuable by the combustion gases and controlled by a command operable, solenoid actuated valve, and means for initially heating and pressurizing the combustion chamber.